//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <unordered_set>

// template <class Value, class Hash = hash<Value>, class Pred = equal_to<Value>,
//           class Alloc = allocator<Value>>
// class unordered_multiset

// size_type erase(const key_type& k);

#include <unordered_set>
#include <string>
#include <cassert>

#include "test_macros.h"
#include "min_allocator.h"

#if TEST_STD_VER >= 11
template <typename Unordered>
bool only_deletions(const Unordered& whole, const Unordered& part) {
  typename Unordered::const_iterator w = whole.begin();
  typename Unordered::const_iterator p = part.begin();

  while (w != whole.end() && p != part.end()) {
    if (*w == *p)
      p++;
    w++;
  }

  return p == part.end();
}
#endif

int main(int, char**) {
  {
    typedef std::unordered_multiset<int> C;
    typedef int P;
    P a[] = {P(1), P(2), P(3), P(4), P(1), P(2)};
    C c(a, a + sizeof(a) / sizeof(a[0]));
    assert(c.erase(5) == 0);
    assert(c.size() == 6);
    assert(c.count(1) == 2);
    assert(c.count(2) == 2);
    assert(c.count(3) == 1);
    assert(c.count(4) == 1);

    assert(c.erase(2) == 2);
    assert(c.size() == 4);
    assert(c.count(1) == 2);
    assert(c.count(3) == 1);
    assert(c.count(4) == 1);

    assert(c.erase(2) == 0);
    assert(c.size() == 4);
    assert(c.count(1) == 2);
    assert(c.count(3) == 1);
    assert(c.count(4) == 1);

    assert(c.erase(4) == 1);
    assert(c.size() == 3);
    assert(c.count(1) == 2);
    assert(c.count(3) == 1);

    assert(c.erase(4) == 0);
    assert(c.size() == 3);
    assert(c.count(1) == 2);
    assert(c.count(3) == 1);

    assert(c.erase(1) == 2);
    assert(c.size() == 1);
    assert(c.count(3) == 1);

    assert(c.erase(1) == 0);
    assert(c.size() == 1);
    assert(c.count(3) == 1);

    assert(c.erase(3) == 1);
    assert(c.size() == 0);

    assert(c.erase(3) == 0);
    assert(c.size() == 0);
  }
#if TEST_STD_VER >= 11
  {
    typedef std::unordered_multiset<int, std::hash<int>, std::equal_to<int>, min_allocator<int>> C;
    typedef int P;
    P a[] = {P(1), P(2), P(3), P(4), P(1), P(2)};
    C c(a, a + sizeof(a) / sizeof(a[0]));
    assert(c.erase(5) == 0);
    assert(c.size() == 6);
    assert(c.count(1) == 2);
    assert(c.count(2) == 2);
    assert(c.count(3) == 1);
    assert(c.count(4) == 1);

    assert(c.erase(2) == 2);
    assert(c.size() == 4);
    assert(c.count(1) == 2);
    assert(c.count(3) == 1);
    assert(c.count(4) == 1);

    assert(c.erase(2) == 0);
    assert(c.size() == 4);
    assert(c.count(1) == 2);
    assert(c.count(3) == 1);
    assert(c.count(4) == 1);

    assert(c.erase(4) == 1);
    assert(c.size() == 3);
    assert(c.count(1) == 2);
    assert(c.count(3) == 1);

    assert(c.erase(4) == 0);
    assert(c.size() == 3);
    assert(c.count(1) == 2);
    assert(c.count(3) == 1);

    assert(c.erase(1) == 2);
    assert(c.size() == 1);
    assert(c.count(3) == 1);

    assert(c.erase(1) == 0);
    assert(c.size() == 1);
    assert(c.count(3) == 1);

    assert(c.erase(3) == 1);
    assert(c.size() == 0);

    assert(c.erase(3) == 0);
    assert(c.size() == 0);
  }
  {
    typedef std::unordered_multiset<int> C;
    C m, m2;
    for (int i = 0; i < 10; ++i) {
      m.insert(i);
      m.insert(i);
      m2.insert(i);
      m2.insert(i);
    }

    C::iterator i = m2.begin();
    int ctr       = 0;
    while (i != m2.end()) {
      if (ctr++ % 2 == 0)
        m2.erase(i++);
      else
        ++i;
    }

    assert(only_deletions(m, m2));
  }
#endif

  return 0;
}
